Drop hammer devices are used to break up concrete, building material, rock, solid ground or the like. By breaking up concrete or building material into smaller pieces, the pieces are reduced to manageable sizes, ready to be removed by excavators and loaders or the like. By breaking up ground, access is allowed to the material or soil below. This is particularly applicable when working with frozen ground such as permafrost.
Other types of machinery used to break up concrete or the like include hydraulic hammers and Pulverisers. Hydraulic hammers are limited to functioning only for their intended purpose, which is to break material into smaller pieces. A number of hydraulic hammers have been broken by operators attempting to use them as a rake or sweep to move broken material away from the breaking zone. Pulverisers are used to grip onto walls or the like and squeeze them, thus crushing the material between. A disadvantage of a nipper is that is has only one intended purpose and therefore other machinery is required if the job has multiple requirements.
If any attempt is made to rake with a drop hammer device, the hammer itself will retract back into the casing at any sign of downward or sideways pressure. The hammer inside the casing is not secured directly to any part of the casing, it is instead held in position by the sides of the casing, but they act only as a guide.
Therefore, any substantially downward or sideways pressure will only push the hammer back into the casing, as the hammer is not secured. Therefore, a drop hammer device cannot usually be used for raking either.
It is common practice for a number of machines to work in conjunction with each other at a breaking site. A drop hammer device mounted on an appropriate piece of machinery will break up the area required. An excavator or loader will then move in to remove the broken material and the drop hammer device will then be moved to the new position for breaking and the cycle continues.
It is also common practice for a single machine to use two attachments, particularly on small jobs. The machine will use one attachment to undertake part of a job, switch between a bucket and a hammer and then continue the job. This type of operation has a number of disadvantages in that the operator must disconnect hoses and reconnect them to the new attachment. Each time the hoses are disconnected, hydraulic fluid will leak out, raising environmental concerns over site contamination. Additionally, the time taken to undertake such a changeover means increased downtime and a higher skill level for the operator.
It can be expensive to use multiple pieces of machinery for demolition and cleanup. These machines are charged out at an hourly rate and either the drop hammer device or removal machinery will sit idle while the other completes its job.
It would be an advantage to have a piece of machinery that could both break material and move it away from the breaking zone so that other machines could work alongside without requiring the drop hammer machinery to halt operation.
Drop hammer devices currently in use cannot fulfil this role in their present configuration as a hammer is configured to move in a substantially vertical direction from a raised to a lowered position. They are not designed to be used in a raking motion as they are not secured to the hammer housing.
It should be appreciated that while drop hammer devices are not designed to be used in a raking motion, they can be operated at angles substantially away from the vertical plane. This freedom of movement away from the vertical allows drop hammer devices to be used to break uneven portions of concrete, and low lying walls or the like and extends the number of places a drop hammer device can be utilised.
A prior art breaker of the applicant's design is used in demolition work connected to an articulated arm of an excavator, skid steer or like machine. The breaker has a housing in which a drop hammer is received. A drive mechanism, enclosed in the housing includes a loop of chain having a dog fixed thereto and a motor for rotating the chain, the dog abutting a projection on the hammer to raise the hammer, moving it away from an opening end of the housing. The hammer is then dropped to extend from opening end of the housing to impact the working surface. Although this tool performs satisfactorily, a number of tool changes on the excavator (e.g. swapping the breaker with a bucket) are required during a demolition operation since the breaker cannot be used for pushing or raking broken material to clear the work area.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning-i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.